Hull's was ''Old''

• Armor-plated warships
• Cavalry is pressing round flank
• The Virginia and the Monitor, e.g.
• Something Old
• Bygone warship
• Old __: Cromwell's nickname
• Oliver Cromwell
• The Virginia and the Monitor, e.g

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Ironside \I"ron*side`\, Ironsides \I"ron*sides`\, prop. n. A nickname for Oliver Cromwell. A nickname for Edmund II of England. --RHUD